Are you asking these questions to get answers or is it purely justing rhetorical? Because I don't think you'd like the answers to those question based on the last part of what you said.
I really want answers. It's like, I'm on the verge of playing the game but this weird feeling is stopping me. I really want answers to my questions, but I feel like at some point, I'll play the game regardless of whether the answers are what I want or if I get answers at all. I'd really appreciate if you could thoroughly answer these:
Who is Rule B?
Does Nael become MC's dark one/part of his harem?
Is there a more powerful being than Nael actively in the story?
Does MC become or will he likely become the most powerful?
Will MC have the most powerful dark one?
Is Claire actually a scheming manipulative bitch who acts against the MC?(Yes, there is hate behind this question. I hate manipulative people.)
For the sake of you playing in the future I won't go into the details.
little bit of spoilers, since everything is explained later in the game.
Yes, Rule B and Gab are the same person (that much is to be expected), and he's also the MC's older brother. Nael IS the strongest Dark One, and will not be part of the harem. Claire in't evil, she is just very cunning and tries to protect Clara. Your questions about the MC can't be answered yet because the game hasn't come that far yet.